/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:		arm_correlate_q7.c
*
* Description:	Correlation of Q7 sequences.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.11 2011/10/18
*    Bug Fix in conv, correlation, partial convolution.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated
*
* Version 0.0.7  2010/06/10
*    Misra-C changes done
*
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupFilters
 */

/**
 * @addtogroup Corr
 * @{
 */

/**
 * @brief Correlation of Q7 sequences.
 * @param[in] *pSrcA points to the first input sequence.
 * @param[in] srcALen length of the first input sequence.
 * @param[in] *pSrcB points to the second input sequence.
 * @param[in] srcBLen length of the second input sequence.
 * @param[out] *pDst points to the location where the output result is written.  Length 2 * max(srcALen, srcBLen) - 1.
 * @return none.
 *
 * @details
 * <b>Scaling and Overflow Behavior:</b>
 *
 * \par
 * The function is implemented using a 32-bit internal accumulator.
 * Both the inputs are represented in 1.7 format and multiplications yield a 2.14 result.
 * The 2.14 intermediate results are accumulated in a 32-bit accumulator in 18.14 format.
 * This approach provides 17 guard bits and there is no risk of overflow as long as <code>max(srcALen, srcBLen)<131072</code>.
 * The 18.14 result is then truncated to 18.7 format by discarding the low 7 bits and saturated to 1.7 format.
 *
 * \par
 * Refer the function <code>arm_correlate_opt_q7()</code> for a faster implementation of this function.
 *
 */

void arm_correlate_q7(
    q7_t* pSrcA,
    uint32_t srcALen,
    q7_t* pSrcB,
    uint32_t srcBLen,
    q7_t* pDst)
{


#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */

	q7_t* pIn1;                                    /* inputA pointer               */
	q7_t* pIn2;                                    /* inputB pointer               */
	q7_t* pOut = pDst;                             /* output pointer               */
	q7_t* px;                                      /* Intermediate inputA pointer  */
	q7_t* py;                                      /* Intermediate inputB pointer  */
	q7_t* pSrc1;                                   /* Intermediate pointers        */
	q31_t sum, acc0, acc1, acc2, acc3;             /* Accumulators                  */
	q31_t input1, input2;                          /* temporary variables */
	q15_t in1, in2;                                /* temporary variables */
	q7_t x0, x1, x2, x3, c0, c1;                   /* temporary variables for holding input and coefficient values */
	uint32_t j, k = 0u, count, blkCnt, outBlockSize, blockSize1, blockSize2, blockSize3;  /* loop counter                 */
	int32_t inc = 1;


	/* The algorithm implementation is based on the lengths of the inputs. */
	/* srcB is always made to slide across srcA. */
	/* So srcBLen is always considered as shorter or equal to srcALen */
	/* But CORR(x, y) is reverse of CORR(y, x) */
	/* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
	/* and the destination pointer modifier, inc is set to -1 */
	/* If srcALen > srcBLen, zero pad has to be done to srcB to make the two inputs of same length */
	/* But to improve the performance,
	 * we include zeroes in the output instead of zero padding either of the the inputs*/
	/* If srcALen > srcBLen,
	 * (srcALen - srcBLen) zeroes has to included in the starting of the output buffer */
	/* If srcALen < srcBLen,
	 * (srcALen - srcBLen) zeroes has to included in the ending of the output buffer */
	if(srcALen >= srcBLen) {
		/* Initialization of inputA pointer */
		pIn1 = (pSrcA);

		/* Initialization of inputB pointer */
		pIn2 = (pSrcB);

		/* Number of output samples is calculated */
		outBlockSize = (2u * srcALen) - 1u;

		/* When srcALen > srcBLen, zero padding is done to srcB
		 * to make their lengths equal.
		 * Instead, (outBlockSize - (srcALen + srcBLen - 1))
		 * number of output samples are made zero */
		j = outBlockSize - (srcALen + (srcBLen - 1u));

		/* Updating the pointer position to non zero value */
		pOut += j;

	} else {
		/* Initialization of inputA pointer */
		pIn1 = (pSrcB);

		/* Initialization of inputB pointer */
		pIn2 = (pSrcA);

		/* srcBLen is always considered as shorter or equal to srcALen */
		j = srcBLen;
		srcBLen = srcALen;
		srcALen = j;

		/* CORR(x, y) = Reverse order(CORR(y, x)) */
		/* Hence set the destination pointer to point to the last output sample */
		pOut = pDst + ((srcALen + srcBLen) - 2u);

		/* Destination address modifier is set to -1 */
		inc = -1;

	}

	/* The function is internally
	 * divided into three parts according to the number of multiplications that has to be
	 * taken place between inputA samples and inputB samples. In the first part of the
	 * algorithm, the multiplications increase by one for every iteration.
	 * In the second part of the algorithm, srcBLen number of multiplications are done.
	 * In the third part of the algorithm, the multiplications decrease by one
	 * for every iteration.*/
	/* The algorithm is implemented in three stages.
	 * The loop counters of each stage is initiated here. */
	blockSize1 = srcBLen - 1u;
	blockSize2 = srcALen - (srcBLen - 1u);
	blockSize3 = blockSize1;

	/* --------------------------
	 * Initializations of stage1
	 * -------------------------*/

	/* sum = x[0] * y[srcBlen - 1]
	 * sum = x[0] * y[srcBlen - 2] + x[1] * y[srcBlen - 1]
	 * ....
	 * sum = x[0] * y[0] + x[1] * y[1] +...+ x[srcBLen - 1] * y[srcBLen - 1]
	 */

	/* In this stage the MAC operations are increased by 1 for every iteration.
	   The count variable holds the number of MAC operations performed */
	count = 1u;

	/* Working pointer of inputA */
	px = pIn1;

	/* Working pointer of inputB */
	pSrc1 = pIn2 + (srcBLen - 1u);
	py = pSrc1;

	/* ------------------------
	 * Stage1 process
	 * ----------------------*/

	/* The first stage starts here */
	while(blockSize1 > 0u) {
		/* Accumulator is made zero for every iteration */
		sum = 0;

		/* Apply loop unrolling and compute 4 MACs simultaneously. */
		k = count >> 2;

		/* First part of the processing with loop unrolling.  Compute 4 MACs at a time.
		 ** a second loop below computes MACs for the remaining 1 to 3 samples. */
		while(k > 0u) {
			/* x[0] , x[1] */
			in1 = (q15_t) * px++;
			in2 = (q15_t) * px++;
			input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

			/* y[srcBLen - 4] , y[srcBLen - 3] */
			in1 = (q15_t) * py++;
			in2 = (q15_t) * py++;
			input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

			/* x[0] * y[srcBLen - 4] */
			/* x[1] * y[srcBLen - 3] */
			sum = __SMLAD(input1, input2, sum);

			/* x[2] , x[3] */
			in1 = (q15_t) * px++;
			in2 = (q15_t) * px++;
			input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

			/* y[srcBLen - 2] , y[srcBLen - 1] */
			in1 = (q15_t) * py++;
			in2 = (q15_t) * py++;
			input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

			/* x[2] * y[srcBLen - 2] */
			/* x[3] * y[srcBLen - 1] */
			sum = __SMLAD(input1, input2, sum);


			/* Decrement the loop counter */
			k--;
		}

		/* If the count is not a multiple of 4, compute any remaining MACs here.
		 ** No loop unrolling is used. */
		k = count % 0x4u;

		while(k > 0u) {
			/* Perform the multiply-accumulates */
			/* x[0] * y[srcBLen - 1] */
			sum += (q31_t)((q15_t) * px++ * *py++);

			/* Decrement the loop counter */
			k--;
		}

		/* Store the result in the accumulator in the destination buffer. */
		*pOut = (q7_t)(__SSAT(sum >> 7, 8));
		/* Destination pointer is updated according to the address modifier, inc */
		pOut += inc;

		/* Update the inputA and inputB pointers for next MAC calculation */
		py = pSrc1 - count;
		px = pIn1;

		/* Increment the MAC count */
		count++;

		/* Decrement the loop counter */
		blockSize1--;
	}

	/* --------------------------
	 * Initializations of stage2
	 * ------------------------*/

	/* sum = x[0] * y[0] + x[1] * y[1] +...+ x[srcBLen-1] * y[srcBLen-1]
	 * sum = x[1] * y[0] + x[2] * y[1] +...+ x[srcBLen] * y[srcBLen-1]
	 * ....
	 * sum = x[srcALen-srcBLen-2] * y[0] + x[srcALen-srcBLen-1] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
	 */

	/* Working pointer of inputA */
	px = pIn1;

	/* Working pointer of inputB */
	py = pIn2;

	/* count is index by which the pointer pIn1 to be incremented */
	count = 0u;

	/* -------------------
	 * Stage2 process
	 * ------------------*/

	/* Stage2 depends on srcBLen as in this stage srcBLen number of MACS are performed.
	 * So, to loop unroll over blockSize2,
	 * srcBLen should be greater than or equal to 4 */
	if(srcBLen >= 4u) {
		/* Loop unroll over blockSize2, by 4 */
		blkCnt = blockSize2 >> 2u;

		while(blkCnt > 0u) {
			/* Set all accumulators to zero */
			acc0 = 0;
			acc1 = 0;
			acc2 = 0;
			acc3 = 0;

			/* read x[0], x[1], x[2] samples */
			x0 = *px++;
			x1 = *px++;
			x2 = *px++;

			/* Apply loop unrolling and compute 4 MACs simultaneously. */
			k = srcBLen >> 2u;

			/* First part of the processing with loop unrolling.  Compute 4 MACs at a time.
			 ** a second loop below computes MACs for the remaining 1 to 3 samples. */
			do {
				/* Read y[0] sample */
				c0 = *py++;
				/* Read y[1] sample */
				c1 = *py++;

				/* Read x[3] sample */
				x3 = *px++;

				/* x[0] and x[1] are packed */
				in1 = (q15_t) x0;
				in2 = (q15_t) x1;

				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* y[0] and y[1] are packed */
				in1 = (q15_t) c0;
				in2 = (q15_t) c1;

				input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* acc0 += x[0] * y[0] + x[1] * y[1]  */
				acc0 = __SMLAD(input1, input2, acc0);

				/* x[1] and x[2] are packed */
				in1 = (q15_t) x1;
				in2 = (q15_t) x2;

				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* acc1 += x[1] * y[0] + x[2] * y[1] */
				acc1 = __SMLAD(input1, input2, acc1);

				/* x[2] and x[3] are packed */
				in1 = (q15_t) x2;
				in2 = (q15_t) x3;

				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* acc2 += x[2] * y[0] + x[3] * y[1]  */
				acc2 = __SMLAD(input1, input2, acc2);

				/* Read x[4] sample */
				x0 = *(px++);

				/* x[3] and x[4] are packed */
				in1 = (q15_t) x3;
				in2 = (q15_t) x0;

				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* acc3 += x[3] * y[0] + x[4] * y[1]  */
				acc3 = __SMLAD(input1, input2, acc3);

				/* Read y[2] sample */
				c0 = *py++;
				/* Read y[3] sample */
				c1 = *py++;

				/* Read x[5] sample */
				x1 = *px++;

				/* x[2] and x[3] are packed */
				in1 = (q15_t) x2;
				in2 = (q15_t) x3;

				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* y[2] and y[3] are packed */
				in1 = (q15_t) c0;
				in2 = (q15_t) c1;

				input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* acc0 += x[2] * y[2] + x[3] * y[3]  */
				acc0 = __SMLAD(input1, input2, acc0);

				/* x[3] and x[4] are packed */
				in1 = (q15_t) x3;
				in2 = (q15_t) x0;

				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* acc1 += x[3] * y[2] + x[4] * y[3]  */
				acc1 = __SMLAD(input1, input2, acc1);

				/* x[4] and x[5] are packed */
				in1 = (q15_t) x0;
				in2 = (q15_t) x1;

				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* acc2 += x[4] * y[2] + x[5] * y[3]  */
				acc2 = __SMLAD(input1, input2, acc2);

				/* Read x[6] sample */
				x2 = *px++;

				/* x[5] and x[6] are packed */
				in1 = (q15_t) x1;
				in2 = (q15_t) x2;

				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* acc3 += x[5] * y[2] + x[6] * y[3]  */
				acc3 = __SMLAD(input1, input2, acc3);

			} while(--k);

			/* If the srcBLen is not a multiple of 4, compute any remaining MACs here.
			 ** No loop unrolling is used. */
			k = srcBLen % 0x4u;

			while(k > 0u) {
				/* Read y[4] sample */
				c0 = *py++;

				/* Read x[7] sample */
				x3 = *px++;

				/* Perform the multiply-accumulates */
				/* acc0 +=  x[4] * y[4] */
				acc0 += ((q15_t) x0 * c0);
				/* acc1 +=  x[5] * y[4] */
				acc1 += ((q15_t) x1 * c0);
				/* acc2 +=  x[6] * y[4] */
				acc2 += ((q15_t) x2 * c0);
				/* acc3 +=  x[7] * y[4] */
				acc3 += ((q15_t) x3 * c0);

				/* Reuse the present samples for the next MAC */
				x0 = x1;
				x1 = x2;
				x2 = x3;

				/* Decrement the loop counter */
				k--;
			}

			/* Store the result in the accumulator in the destination buffer. */
			*pOut = (q7_t)(__SSAT(acc0 >> 7, 8));
			/* Destination pointer is updated according to the address modifier, inc */
			pOut += inc;

			*pOut = (q7_t)(__SSAT(acc1 >> 7, 8));
			pOut += inc;

			*pOut = (q7_t)(__SSAT(acc2 >> 7, 8));
			pOut += inc;

			*pOut = (q7_t)(__SSAT(acc3 >> 7, 8));
			pOut += inc;

			count += 4u;
			/* Update the inputA and inputB pointers for next MAC calculation */
			px = pIn1 + count;
			py = pIn2;

			/* Decrement the loop counter */
			blkCnt--;
		}

		/* If the blockSize2 is not a multiple of 4, compute any remaining output samples here.
		 ** No loop unrolling is used. */
		blkCnt = blockSize2 % 0x4u;

		while(blkCnt > 0u) {
			/* Accumulator is made zero for every iteration */
			sum = 0;

			/* Apply loop unrolling and compute 4 MACs simultaneously. */
			k = srcBLen >> 2u;

			/* First part of the processing with loop unrolling.  Compute 4 MACs at a time.
			 ** a second loop below computes MACs for the remaining 1 to 3 samples. */
			while(k > 0u) {
				/* Reading two inputs of SrcA buffer and packing */
				in1 = (q15_t) * px++;
				in2 = (q15_t) * px++;
				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* Reading two inputs of SrcB buffer and packing */
				in1 = (q15_t) * py++;
				in2 = (q15_t) * py++;
				input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* Perform the multiply-accumulates */
				sum = __SMLAD(input1, input2, sum);

				/* Reading two inputs of SrcA buffer and packing */
				in1 = (q15_t) * px++;
				in2 = (q15_t) * px++;
				input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* Reading two inputs of SrcB buffer and packing */
				in1 = (q15_t) * py++;
				in2 = (q15_t) * py++;
				input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

				/* Perform the multiply-accumulates */
				sum = __SMLAD(input1, input2, sum);

				/* Decrement the loop counter */
				k--;
			}

			/* If the srcBLen is not a multiple of 4, compute any remaining MACs here.
			 ** No loop unrolling is used. */
			k = srcBLen % 0x4u;

			while(k > 0u) {
				/* Perform the multiply-accumulates */
				sum += ((q15_t) * px++ * *py++);

				/* Decrement the loop counter */
				k--;
			}

			/* Store the result in the accumulator in the destination buffer. */
			*pOut = (q7_t)(__SSAT(sum >> 7, 8));
			/* Destination pointer is updated according to the address modifier, inc */
			pOut += inc;

			/* Increment the pointer pIn1 index, count by 1 */
			count++;

			/* Update the inputA and inputB pointers for next MAC calculation */
			px = pIn1 + count;
			py = pIn2;

			/* Decrement the loop counter */
			blkCnt--;
		}
	} else {
		/* If the srcBLen is not a multiple of 4,
		 * the blockSize2 loop cannot be unrolled by 4 */
		blkCnt = blockSize2;

		while(blkCnt > 0u) {
			/* Accumulator is made zero for every iteration */
			sum = 0;

			/* Loop over srcBLen */
			k = srcBLen;

			while(k > 0u) {
				/* Perform the multiply-accumulate */
				sum += ((q15_t) * px++ * *py++);

				/* Decrement the loop counter */
				k--;
			}

			/* Store the result in the accumulator in the destination buffer. */
			*pOut = (q7_t)(__SSAT(sum >> 7, 8));
			/* Destination pointer is updated according to the address modifier, inc */
			pOut += inc;

			/* Increment the MAC count */
			count++;

			/* Update the inputA and inputB pointers for next MAC calculation */
			px = pIn1 + count;
			py = pIn2;


			/* Decrement the loop counter */
			blkCnt--;
		}
	}

	/* --------------------------
	 * Initializations of stage3
	 * -------------------------*/

	/* sum += x[srcALen-srcBLen+1] * y[0] + x[srcALen-srcBLen+2] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
	 * sum += x[srcALen-srcBLen+2] * y[0] + x[srcALen-srcBLen+3] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
	 * ....
	 * sum +=  x[srcALen-2] * y[0] + x[srcALen-1] * y[1]
	 * sum +=  x[srcALen-1] * y[0]
	 */

	/* In this stage the MAC operations are decreased by 1 for every iteration.
	   The count variable holds the number of MAC operations performed */
	count = srcBLen - 1u;

	/* Working pointer of inputA */
	pSrc1 = pIn1 + (srcALen - (srcBLen - 1u));
	px = pSrc1;

	/* Working pointer of inputB */
	py = pIn2;

	/* -------------------
	 * Stage3 process
	 * ------------------*/

	while(blockSize3 > 0u) {
		/* Accumulator is made zero for every iteration */
		sum = 0;

		/* Apply loop unrolling and compute 4 MACs simultaneously. */
		k = count >> 2u;

		/* First part of the processing with loop unrolling.  Compute 4 MACs at a time.
		 ** a second loop below computes MACs for the remaining 1 to 3 samples. */
		while(k > 0u) {
			/* x[srcALen - srcBLen + 1] , x[srcALen - srcBLen + 2]  */
			in1 = (q15_t) * px++;
			in2 = (q15_t) * px++;
			input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

			/* y[0] , y[1] */
			in1 = (q15_t) * py++;
			in2 = (q15_t) * py++;
			input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

			/* sum += x[srcALen - srcBLen + 1] * y[0] */
			/* sum += x[srcALen - srcBLen + 2] * y[1] */
			sum = __SMLAD(input1, input2, sum);

			/* x[srcALen - srcBLen + 3] , x[srcALen - srcBLen + 4] */
			in1 = (q15_t) * px++;
			in2 = (q15_t) * px++;
			input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

			/* y[2] , y[3] */
			in1 = (q15_t) * py++;
			in2 = (q15_t) * py++;
			input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);

			/* sum += x[srcALen - srcBLen + 3] * y[2] */
			/* sum += x[srcALen - srcBLen + 4] * y[3] */
			sum = __SMLAD(input1, input2, sum);

			/* Decrement the loop counter */
			k--;
		}

		/* If the count is not a multiple of 4, compute any remaining MACs here.
		 ** No loop unrolling is used. */
		k = count % 0x4u;

		while(k > 0u) {
			/* Perform the multiply-accumulates */
			sum += ((q15_t) * px++ * *py++);

			/* Decrement the loop counter */
			k--;
		}

		/* Store the result in the accumulator in the destination buffer. */
		*pOut = (q7_t)(__SSAT(sum >> 7, 8));
		/* Destination pointer is updated according to the address modifier, inc */
		pOut += inc;

		/* Update the inputA and inputB pointers for next MAC calculation */
		px = ++pSrc1;
		py = pIn2;

		/* Decrement the MAC count */
		count--;

		/* Decrement the loop counter */
		blockSize3--;
	}

#else

	/* Run the below code for Cortex-M0 */

	q7_t* pIn1 = pSrcA;                            /* inputA pointer */
	q7_t* pIn2 = pSrcB + (srcBLen - 1u);           /* inputB pointer */
	q31_t sum;                                     /* Accumulator */
	uint32_t i = 0u, j;                            /* loop counters */
	uint32_t inv = 0u;                             /* Reverse order flag */
	uint32_t tot = 0u;                             /* Length */

	/* The algorithm implementation is based on the lengths of the inputs. */
	/* srcB is always made to slide across srcA. */
	/* So srcBLen is always considered as shorter or equal to srcALen */
	/* But CORR(x, y) is reverse of CORR(y, x) */
	/* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
	/* and a varaible, inv is set to 1 */
	/* If lengths are not equal then zero pad has to be done to  make the two
	 * inputs of same length. But to improve the performance, we include zeroes
	 * in the output instead of zero padding either of the the inputs*/
	/* If srcALen > srcBLen, (srcALen - srcBLen) zeroes has to included in the
	 * starting of the output buffer */
	/* If srcALen < srcBLen, (srcALen - srcBLen) zeroes has to included in the
	 * ending of the output buffer */
	/* Once the zero padding is done the remaining of the output is calcualted
	 * using convolution but with the shorter signal time shifted. */

	/* Calculate the length of the remaining sequence */
	tot = ((srcALen + srcBLen) - 2u);

	if(srcALen > srcBLen) {
		/* Calculating the number of zeros to be padded to the output */
		j = srcALen - srcBLen;

		/* Initialise the pointer after zero padding */
		pDst += j;
	}

	else if(srcALen < srcBLen) {
		/* Initialization to inputB pointer */
		pIn1 = pSrcB;

		/* Initialization to the end of inputA pointer */
		pIn2 = pSrcA + (srcALen - 1u);

		/* Initialisation of the pointer after zero padding */
		pDst = pDst + tot;

		/* Swapping the lengths */
		j = srcALen;
		srcALen = srcBLen;
		srcBLen = j;

		/* Setting the reverse flag */
		inv = 1;

	}

	/* Loop to calculate convolution for output length number of times */
	for(i = 0u; i <= tot; i++) {
		/* Initialize sum with zero to carry on MAC operations */
		sum = 0;

		/* Loop to perform MAC operations according to convolution equation */
		for(j = 0u; j <= i; j++) {
			/* Check the array limitations */
			if((((i - j) < srcBLen) && (j < srcALen))) {
				/* z[i] += x[i-j] * y[j] */
				sum += ((q15_t) pIn1[j] * pIn2[-((int32_t) i - j)]);
			}
		}

		/* Store the output in the destination buffer */
		if(inv == 1)
			*pDst-- = (q7_t) __SSAT((sum >> 7u), 8u);
		else
			*pDst++ = (q7_t) __SSAT((sum >> 7u), 8u);
	}

#endif /*   #ifndef ARM_MATH_CM0 */

}

/**
 * @} end of Corr group
 */
